4 This file contains descriptions of new features that have been added to Exim.
5 Before a formal release, there may be quite a lot of detail so that people can
6 test from the snapshots or the Git before the documentation is updated. Once
7 the documentation is updated, this file is reduced to a short list.
12 1. PKG_CONFIG_PATH can now be set in Local/Makefile;
13 wildcards will be expanded, values are collapsed.
15 2. The ${readsocket } expansion now takes an option to not shutdown the
16 connection after sending the query string. The default remains to do so.
18 3. An smtp transport option "hosts_noproxy_tls" to control whether multiple
19 deliveries on a single TCP connection can maintain a TLS connection
20 open. By default disabled for all hosts, doing so saves the cost of
21 making new TLS sessions, at the cost of having to proxy the data via
22 another process. Logging is also affected.
24 4. A malware connection type for the FPSCAND protocol.
26 5. An option for recipient verify callouts to hold the connection open for
27 further recipients and for delivery.
29 6. The reproducible build $SOURCE_DATE_EPOCH environment variable is now
32 7. Optionally, an alternate format for spool data-files which matches the
33 wire format - meaning more efficient reception and transmission (at the
34 cost of difficulty with standard Unix tools). Only used for messages
35 received using the ESMTP CHUNKING option, and when a new main-section
36 option "spool_wireformat" (false by default) is set.
38 8. New main configuration option "commandline_checks_require_admin" to
39 restrict who can use various introspection options.
41 9. New option modifier "no_check" for quota and quota_filecount
44 10. Variable $smtp_command_history returning a comma-sep list of recent
47 11. Millisecond timetamps in logs, on log_selector "millisec". Also affects
48 log elements QT, DT and D, and timstamps in debug output.
50 12. TCP Fast Open logging. As a server, logs when the SMTP banner was sent
51 while still in SYN_RECV state; as a client logs when the connection
52 is opened with a TFO cookie.
54 13. DKIM support for multiple signing, by domain and/or key-selector.
55 DKIM support for multiple hashes, and for alternate-identity tags.
57 14. Exipick understands -C|--config for an alternative Exim
60 15. TCP Fast Open used, with data-on-SYN, for client SMTP via SOCKS5 proxy,
61 for ${readsocket } expansions, and for ClamAV.
67 1. Allow relative config file names for ".include"
69 2. A main-section config option "debug_store" to control the checks on
70 variable locations during store-reset. Normally false but can be enabled
71 when a memory corrution issue is suspected on a production system.
77 1. The new perl_taintmode option allows to run the embedded perl
78 interpreter in taint mode.
80 2. New log_selector: dnssec, adds a "DS" tag to acceptance and delivery lines.
82 3. Speculative debugging, via a "kill" option to the "control=debug" ACL
85 4. New expansion item ${sha3:<string>} / ${sha3_<N>:<string>}.
86 N can be 224, 256 (default), 384, 512.
87 With GnuTLS 3.5.0 or later, only.
89 5. Facility for named queues: A command-line argument can specify
90 the queue name for a queue operation, and an ACL modifier can set
91 the queue to be used for a message. A $queue_name variable gives
94 6. New expansion operators base32/base32d.
96 7. The CHUNKING ESMTP extension from RFC 3030. May give some slight
97 performance increase and network load decrease. Main config option
98 chunking_advertise_hosts, and smtp transport option hosts_try_chunking
101 8. LMDB lookup support, as Experimental. Patch supplied by Andrew Colin Kissa.
103 9. Expansion operator escape8bit, like escape but not touching newline etc..
105 10. Feature macros, generated from compile options. All start with "_HAVE_"
106 and go on with some roughly recognisable name. Driver macros, for
107 router, transport and authentication drivers; names starting with "_DRIVER_".
108 Option macros, for each configuration-file option; all start with "_OPT_".
109 Use the "-bP macros" command-line option to see what is present.
111 11. Integer values for options can take a "G" multiplier.
113 12. defer=pass option for the ACL control cutthrough_delivery, to reflect 4xx
114 returns from the target back to the initiator, rather than spooling the
117 13. New built-in constants available for tls_dhparam and default changed.
119 14. If built with EXPERIMENTAL_QUEUEFILE, a queuefile transport, for writing
120 out copies of the message spool files for use by 3rd-party scanners.
122 15. A new option on the smtp transport, hosts_try_fastopen. If the system
123 supports it (on Linux it must be enabled in the kernel by the sysadmin)
124 try to use RFC 7413 "TCP Fast Open". No data is sent on the SYN segment
125 but it permits a peer that also supports the facility to send its SMTP
126 banner immediately after the SYN,ACK segment rather then waiting for
127 another ACK - so saving up to one roundtrip time. Because it requires
128 previous communication with the peer (we save a cookie from it) this
129 will only become active on frequently-contacted destinations.
131 16. A new syslog_pid option to suppress PID duplication in syslog lines.
137 1. The ACL conditions regex and mime_regex now capture substrings
138 into numeric variables $regex1 to 9, like the "match" expansion condition.
140 2. New $callout_address variable records the address used for a spam=,
141 malware= or verify= callout.
143 3. Transports now take a "max_parallel" option, to limit concurrency.
145 4. Expansion operators ${ipv6norm:<string>} and ${ipv6denorm:<string>}.
146 The latter expands to a 8-element colon-sep set of hex digits including
147 leading zeroes. A trailing ipv4-style dotted-decimal set is converted
148 to hex. Pure ipv4 addresses are converted to IPv4-mapped IPv6.
149 The former operator strips leading zeroes and collapses the longest
150 set of 0-groups to a double-colon.
152 5. New "-bP config" support, to dump the effective configuration.
154 6. New $dkim_key_length variable.
156 7. New base64d and base64 expansion items (the existing str2b64 being a
157 synonym of the latter). Add support in base64 for certificates.
159 8. New main configuration option "bounce_return_linesize_limit" to
160 avoid oversize bodies in bounces. The default value matches RFC
163 9. New $initial_cwd expansion variable.
169 1. Support for using the system standard CA bundle.
171 2. New expansion items $config_file, $config_dir, containing the file
172 and directory name of the main configuration file. Also $exim_version.
174 3. New "malware=" support for Avast.
176 4. New "spam=" variant option for Rspamd.
178 5. Assorted options on malware= and spam= scanners.
180 6. A command-line option to write a comment into the logfile.
182 7. If built with EXPERIMENTAL_SOCKS feature enabled, the smtp transport can
183 be configured to make connections via socks5 proxies.
185 8. If built with EXPERIMENTAL_INTERNATIONAL, support is included for
186 the transmission of UTF-8 envelope addresses.
188 9. If built with EXPERIMENTAL_INTERNATIONAL, an expansion item for a commonly
189 used encoding of Maildir folder names.
191 10. A logging option for slow DNS lookups.
193 11. New ${env {<variable>}} expansion.
195 12. A non-SMTP authenticator using information from TLS client certificates.
197 13. Main option "tls_eccurve" for selecting an Elliptic Curve for TLS.
198 Patch originally by Wolfgang Breyha.
200 14. Main option "dns_trust_aa" for trusting your local nameserver at the
201 same level as DNSSEC.
207 1. If built with EXPERIMENTAL_DANE feature enabled, Exim will follow the
208 DANE SMTP draft to assess a secure chain of trust of the certificate
209 used to establish the TLS connection based on a TLSA record in the
210 domain of the sender.
212 2. The EXPERIMENTAL_TPDA feature has been renamed to EXPERIMENTAL_EVENT
213 and several new events have been created. The reason is because it has
214 been expanded beyond just firing events during the transport phase. Any
215 existing TPDA transport options will have to be rewritten to use a new
216 $event_name expansion variable in a condition. Refer to the
217 experimental-spec.txt for details and examples.
219 3. The EXPERIMENTAL_CERTNAMES features is an enhancement to verify that
220 server certs used for TLS match the result of the MX lookup. It does
221 not use the same mechanism as DANE.
231 1. If built with the EXPERIMENTAL_PROXY feature enabled, Exim can be
232 configured to expect an initial header from a proxy that will make the
233 actual external source IP:host be used in exim instead of the IP of the
234 proxy that is connecting to it.
236 2. New verify option header_names_ascii, which will check to make sure
237 there are no non-ASCII characters in header names. Exim itself handles
238 those non-ASCII characters, but downstream apps may not, so Exim can
239 detect and reject if those characters are present.
241 3. New expansion operator ${utf8clean:string} to replace malformed UTF8
242 codepoints with valid ones.
244 4. New malware type "sock". Talks over a Unix or TCP socket, sending one
245 command line and matching a regex against the return data for trigger
246 and a second regex to extract malware_name. The mail spoolfile name can
247 be included in the command line.
249 5. The smtp transport now supports options "tls_verify_hosts" and
250 "tls_try_verify_hosts". If either is set the certificate verification
251 is split from the encryption operation. The default remains that a failed
252 verification cancels the encryption.
254 6. New SERVERS override of default ldap server list. In the ACLs, an ldap
255 lookup can now set a list of servers to use that is different from the
258 7. New command-line option -C for exiqgrep to specify alternate exim.conf
259 file when searching the queue.
261 8. OCSP now supports GnuTLS also, if you have version 3.1.3 or later of that.
263 9. Support for DNSSEC on outbound connections.
265 10. New variables "tls_(in,out)_(our,peer)cert" and expansion item
266 "certextract" to extract fields from them. Hash operators md5 and sha1
267 work over them for generating fingerprints, and a new sha256 operator
270 11. PRDR is now supported dy default.
272 12. OCSP stapling is now supported by default.
274 13. If built with the EXPERIMENTAL_DSN feature enabled, Exim will output
275 Delivery Status Notification messages in MIME format, and negotiate
276 DSN features per RFC 3461.
282 1. New command-line option -bI:sieve will list all supported sieve extensions
283 of this Exim build on standard output, one per line.
284 ManageSieve (RFC 5804) providers managing scripts for use by Exim should
285 query this to establish the correct list to include in the protocol's
286 SIEVE capability line.
288 2. If the -n option is combined with the -bP option, then the name of an
289 emitted option is not output, only the value (if visible to you).
290 For instance, "exim -n -bP pid_file_path" should just emit a pathname
291 followed by a newline, and no other text.
293 3. When built with SUPPORT_TLS and USE_GNUTLS, the SMTP transport driver now
294 has a "tls_dh_min_bits" option, to set the minimum acceptable number of
295 bits in the Diffie-Hellman prime offered by a server (in DH ciphersuites)
296 acceptable for security. (Option accepted but ignored if using OpenSSL).
297 Defaults to 1024, the old value. May be lowered only to 512, or raised as
298 far as you like. Raising this may hinder TLS interoperability with other
299 sites and is not currently recommended. Lowering this will permit you to
300 establish a TLS session which is not as secure as you might like.
302 Unless you really know what you are doing, leave it alone.
304 4. If not built with DISABLE_DNSSEC, Exim now has the main option
305 dns_dnssec_ok; if set to 1 then Exim will initialise the resolver library
306 to send the DO flag to your recursive resolver. If you have a recursive
307 resolver, which can set the Authenticated Data (AD) flag in results, Exim
308 can now detect this. Exim does not perform validation itself, instead
309 relying upon a trusted path to the resolver.
311 Current status: work-in-progress; $sender_host_dnssec variable added.
313 5. DSCP support for outbound connections: on a transport using the smtp driver,
314 set "dscp = ef", for instance, to cause the connections to have the relevant
315 DSCP (IPv4 TOS or IPv6 TCLASS) value in the header.
317 Similarly for inbound connections, there is a new control modifier, dscp,
318 so "warn control = dscp/ef" in the connect ACL, or after authentication.
320 Supported values depend upon system libraries. "exim -bI:dscp" to list the
321 ones Exim knows of. You can also set a raw number 0..0x3F.
323 6. The -G command-line flag is no longer ignored; it is now equivalent to an
324 ACL setting "control = suppress_local_fixups". The -L command-line flag
325 is now accepted and forces use of syslog, with the provided tag as the
326 process name. A few other flags used by Sendmail are now accepted and
329 7. New cutthrough routing feature. Requested by a "control = cutthrough_delivery"
330 ACL modifier; works for single-recipient mails which are received on and
331 deliverable via SMTP. Using the connection made for a recipient verify,
332 if requested before the verify, or a new one made for the purpose while
333 the inbound connection is still active. The bulk of the mail item is copied
334 direct from the inbound socket to the outbound (as well as the spool file).
335 When the source notifies the end of data, the data acceptance by the destination
336 is negotiated before the acceptance is sent to the source. If the destination
337 does not accept the mail item, for example due to content-scanning, the item
338 is not accepted from the source and therefore there is no need to generate
339 a bounce mail. This is of benefit when providing a secondary-MX service.
340 The downside is that delays are under the control of the ultimate destination
343 The Received-by: header on items delivered by cutthrough is generated
344 early in reception rather than at the end; this will affect any timestamp
345 included. The log line showing delivery is recorded before that showing
346 reception; it uses a new ">>" tag instead of "=>".
348 To support the feature, verify-callout connections can now use ESMTP and TLS.
349 The usual smtp transport options are honoured, plus a (new, default everything)
350 hosts_verify_avoid_tls.
352 New variable families named tls_in_cipher, tls_out_cipher etc. are introduced
353 for specific access to the information for each connection. The old names
354 are present for now but deprecated.
356 Not yet supported: IGNOREQUOTA, SIZE, PIPELINING.
358 8. New expansion operators ${listnamed:name} to get the content of a named list
359 and ${listcount:string} to count the items in a list.
361 9. New global option "gnutls_allow_auto_pkcs11", defaults false. The GnuTLS
362 rewrite in 4.80 combines with GnuTLS 2.12.0 or later, to autoload PKCS11
363 modules. For some situations this is desirable, but we expect admin in
364 those situations to know they want the feature. More commonly, it means
365 that GUI user modules get loaded and are broken by the setuid Exim being
366 unable to access files specified in environment variables and passed
367 through, thus breakage. So we explicitly inhibit the PKCS11 initialisation
368 unless this new option is set.
370 Some older OS's with earlier versions of GnuTLS might not have pkcs11 ability,
371 so have also added a build option which can be used to build Exim with GnuTLS
372 but without trying to use any kind of PKCS11 support. Uncomment this in the
375 AVOID_GNUTLS_PKCS11=yes
377 10. The "acl = name" condition on an ACL now supports optional arguments.
378 New expansion item "${acl {name}{arg}...}" and expansion condition
379 "acl {{name}{arg}...}" are added. In all cases up to nine arguments
380 can be used, appearing in $acl_arg1 to $acl_arg9 for the called ACL.
381 Variable $acl_narg contains the number of arguments. If the ACL sets
382 a "message =" value this becomes the result of the expansion item,
383 or the value of $value for the expansion condition. If the ACL returns
384 accept the expansion condition is true; if reject, false. A defer
385 return results in a forced fail.
387 11. Routers and transports can now have multiple headers_add and headers_remove
388 option lines. The concatenated list is used.
390 12. New ACL modifier "remove_header" can remove headers before message gets
391 handled by routers/transports.
393 13. New dnsdb lookup pseudo-type "a+". A sequence of "a6" (if configured),
394 "aaaa" and "a" lookups is done and the full set of results returned.
396 14. New expansion variable $headers_added with content from ACL add_header
397 modifier (but not yet added to message).
399 15. New 8bitmime status logging option for received messages. Log field "M8S".
401 16. New authenticated_sender logging option, adding to log field "A".
403 17. New expansion variables $router_name and $transport_name. Useful
404 particularly for debug_print as -bt command-line option does not
405 require privilege whereas -d does.
407 18. If built with EXPERIMENTAL_PRDR, per-recipient data responses per a
408 proposed extension to SMTP from Eric Hall.
410 19. The pipe transport has gained the force_command option, to allow
411 decorating commands from user .forward pipe aliases with prefix
412 wrappers, for instance.
414 20. Callout connections can now AUTH; the same controls as normal delivery
417 21. Support for DMARC, using opendmarc libs, can be enabled. It adds new
418 options: dmarc_forensic_sender, dmarc_history_file, and dmarc_tld_file.
419 It adds new expansion variables $dmarc_ar_header, $dmarc_status,
420 $dmarc_status_text, and $dmarc_used_domain. It adds a new acl modifier
421 dmarc_status. It adds new control flags dmarc_disable_verify and
422 dmarc_enable_forensic. The default for the dmarc_tld_file option is
423 "/etc/exim/opendmarc.tlds" and can be changed via EDITME.
425 22. Add expansion variable $authenticated_fail_id, which is the username
426 provided to the authentication method which failed. It is available
427 for use in subsequent ACL processing (typically quit or notquit ACLs).
429 23. New ACL modifier "udpsend" can construct a UDP packet to send to a given
432 24. New ${hexquote:..string..} expansion operator converts non-printable
433 characters in the string to \xNN form.
435 25. Experimental TPDA (Transport Post Delivery Action) function added.
436 Patch provided by Axel Rau.
438 26. Experimental Redis lookup added. Patch provided by Warren Baker.
444 1. New authenticator driver, "gsasl". Server-only (at present).
445 This is a SASL interface, licensed under GPL, which can be found at
446 http://www.gnu.org/software/gsasl/.
447 This system does not provide sources of data for authentication, so
448 careful use needs to be made of the conditions in Exim.
450 2. New authenticator driver, "heimdal_gssapi". Server-only.
451 A replacement for using cyrus_sasl with Heimdal, now that $KRB5_KTNAME
452 is no longer honoured for setuid programs by Heimdal. Use the
453 "server_keytab" option to point to the keytab.
455 3. The "pkg-config" system can now be used when building Exim to reference
456 cflags and library information for lookups and authenticators, rather
457 than having to update "CFLAGS", "AUTH_LIBS", "LOOKUP_INCLUDE" and
458 "LOOKUP_LIBS" directly. Similarly for handling the TLS library support
459 without adjusting "TLS_INCLUDE" and "TLS_LIBS".
461 In addition, setting PCRE_CONFIG=yes will query the pcre-config tool to
462 find the headers and libraries for PCRE.
464 4. New expansion variable $tls_bits.
466 5. New lookup type, "dbmjz". Key is an Exim list, the elements of which will
467 be joined together with ASCII NUL characters to construct the key to pass
468 into the DBM library. Can be used with gsasl to access sasldb2 files as
471 6. OpenSSL now supports TLS1.1 and TLS1.2 with OpenSSL 1.0.1.
473 Avoid release 1.0.1a if you can. Note that the default value of
474 "openssl_options" is no longer "+dont_insert_empty_fragments", as that
475 increased susceptibility to attack. This may still have interoperability
476 implications for very old clients (see version 4.31 change 37) but
477 administrators can choose to make the trade-off themselves and restore
478 compatibility at the cost of session security.
480 7. Use of the new expansion variable $tls_sni in the main configuration option
481 tls_certificate will cause Exim to re-expand the option, if the client
482 sends the TLS Server Name Indication extension, to permit choosing a
483 different certificate; tls_privatekey will also be re-expanded. You must
484 still set these options to expand to valid files when $tls_sni is not set.
486 The SMTP Transport has gained the option tls_sni, which will set a hostname
487 for outbound TLS sessions, and set $tls_sni too.
489 A new log_selector, +tls_sni, has been added, to log received SNI values
490 for Exim as a server.
492 8. The existing "accept_8bitmime" option now defaults to true. This means
493 that Exim is deliberately not strictly RFC compliant. We're following
494 Dan Bernstein's advice in http://cr.yp.to/smtp/8bitmime.html by default.
495 Those who disagree, or know that they are talking to mail servers that,
496 even today, are not 8-bit clean, need to turn off this option.
498 9. Exim can now be started with -bw (with an optional timeout, given as
499 -bw<timespec>). With this, stdin at startup is a socket that is
500 already listening for connections. This has a more modern name of
501 "socket activation", but forcing the activated socket to fd 0. We're
502 interested in adding more support for modern variants.
504 10. ${eval } now uses 64-bit values on supporting platforms. A new "G" suffix
505 for numbers indicates multiplication by 1024^3.
507 11. The GnuTLS support has been revamped; the three options gnutls_require_kx,
508 gnutls_require_mac & gnutls_require_protocols are no longer supported.
509 tls_require_ciphers is now parsed by gnutls_priority_init(3) as a priority
510 string, documentation for which is at:
511 http://www.gnutls.org/manual/html_node/Priority-Strings.html
513 SNI support has been added to Exim's GnuTLS integration too.
515 For sufficiently recent GnuTLS libraries, ${randint:..} will now use
516 gnutls_rnd(), asking for GNUTLS_RND_NONCE level randomness.
518 12. With OpenSSL, if built with EXPERIMENTAL_OCSP, a new option tls_ocsp_file
519 is now available. If the contents of the file are valid, then Exim will
520 send that back in response to a TLS status request; this is OCSP Stapling.
521 Exim will not maintain the contents of the file in any way: administrators
522 are responsible for ensuring that it is up-to-date.
524 See "experimental-spec.txt" for more details.
526 13. ${lookup dnsdb{ }} supports now SPF record types. They are handled
527 identically to TXT record lookups.
529 14. New expansion variable $tod_epoch_l for higher-precision time.
531 15. New global option tls_dh_max_bits, defaulting to current value of NSS
532 hard-coded limit of DH ephemeral bits, to fix interop problems caused by
533 GnuTLS 2.12 library recommending a bit count higher than NSS supports.
535 16. tls_dhparam now used by both OpenSSL and GnuTLS, can be path or identifier.
536 Option can now be a path or an identifier for a standard prime.
537 If unset, we use the DH prime from section 2.2 of RFC 5114, "ike23".
538 Set to "historic" to get the old GnuTLS behaviour of auto-generated DH
541 17. SSLv2 now disabled by default in OpenSSL. (Never supported by GnuTLS).
542 Use "openssl_options -no_sslv2" to re-enable support, if your OpenSSL
543 install was not built with OPENSSL_NO_SSL2 ("no-ssl2").
549 1. New options for the ratelimit ACL condition: /count= and /unique=.
550 The /noupdate option has been replaced by a /readonly option.
552 2. The SMTP transport's protocol option may now be set to "smtps", to
553 use SSL-on-connect outbound.
555 3. New variable $av_failed, set true if the AV scanner deferred; ie, when
556 there is a problem talking to the AV scanner, or the AV scanner running.
558 4. New expansion conditions, "inlist" and "inlisti", which take simple lists
559 and check if the search item is a member of the list. This does not
560 support named lists, but does subject the list part to string expansion.
562 5. Unless the new EXPAND_LISTMATCH_RHS build option is set when Exim was
563 built, Exim no longer performs string expansion on the second string of
564 the match_* expansion conditions: "match_address", "match_domain",
565 "match_ip" & "match_local_part". Named lists can still be used.
571 1. The global option "dns_use_edns0" may be set to coerce EDNS0 usage on
572 or off in the resolver library.
578 1. In addition to the existing LDAP and LDAP/SSL ("ldaps") support, there
579 is now LDAP/TLS support, given sufficiently modern OpenLDAP client
580 libraries. The following global options have been added in support of
581 this: ldap_ca_cert_dir, ldap_ca_cert_file, ldap_cert_file, ldap_cert_key,
582 ldap_cipher_suite, ldap_require_cert, ldap_start_tls.
584 2. The pipe transport now takes a boolean option, "freeze_signal", default
585 false. When true, if the external delivery command exits on a signal then
586 Exim will freeze the message in the queue, instead of generating a bounce.
588 3. Log filenames may now use %M as an escape, instead of %D (still available).
589 The %M pattern expands to yyyymm, providing month-level resolution.
591 4. The $message_linecount variable is now updated for the maildir_tag option,
592 in the same way as $message_size, to reflect the real number of lines,
593 including any header additions or removals from transport.
595 5. When contacting a pool of SpamAssassin servers configured in spamd_address,
596 Exim now selects entries randomly, to better scale in a cluster setup.
602 1. SECURITY FIX: privilege escalation flaw fixed. On Linux (and only Linux)
603 the flaw permitted the Exim run-time user to cause root to append to
604 arbitrary files of the attacker's choosing, with the content based
605 on content supplied by the attacker.
607 2. Exim now supports loading some lookup types at run-time, using your
608 platform's dlopen() functionality. This has limited platform support
609 and the intention is not to support every variant, it's limited to
610 dlopen(). This permits the main Exim binary to not be linked against
611 all the libraries needed for all the lookup types.
617 NOTE: this version is not guaranteed backwards-compatible, please read the
618 items below carefully
620 1. A new main configuration option, "openssl_options", is available if Exim
621 is built with SSL support provided by OpenSSL. The option allows
622 administrators to specify OpenSSL options to be used on connections;
623 typically this is to set bug compatibility features which the OpenSSL
624 developers have not enabled by default. There may be security
625 consequences for certain options, so these should not be changed
628 2. A new pipe transport option, "permit_coredumps", may help with problem
629 diagnosis in some scenarios. Note that Exim is typically installed as
630 a setuid binary, which on most OSes will inhibit coredumps by default,
631 so that safety mechanism would have to be overridden for this option to
632 be able to take effect.
634 3. ClamAV 0.95 is now required for ClamAV support in Exim, unless
635 Local/Makefile sets: WITH_OLD_CLAMAV_STREAM=yes
636 Note that this switches Exim to use a new API ("INSTREAM") and a future
637 release of ClamAV will remove support for the old API ("STREAM").
639 The av_scanner option, when set to "clamd", now takes an optional third
640 part, "local", which causes Exim to pass a filename to ClamAV instead of
641 the file content. This is the same behaviour as when clamd is pointed at
642 a Unix-domain socket. For example:
644 av_scanner = clamd:192.0.2.3 1234:local
646 ClamAV's ExtendedDetectionInfo response format is now handled.
648 4. There is now a -bmalware option, restricted to admin users. This option
649 takes one parameter, a filename, and scans that file with Exim's
650 malware-scanning framework. This is intended purely as a debugging aid
651 to ensure that Exim's scanning is working, not to replace other tools.
652 Note that the ACL framework is not invoked, so if av_scanner references
653 ACL variables without a fallback then this will fail.
655 5. There is a new expansion operator, "reverse_ip", which will reverse IP
656 addresses; IPv4 into dotted quad, IPv6 into dotted nibble. Examples:
658 ${reverse_ip:192.0.2.4}
660 ${reverse_ip:2001:0db8:c42:9:1:abcd:192.0.2.3}
661 -> 3.0.2.0.0.0.0.c.d.c.b.a.1.0.0.0.9.0.0.0.2.4.c.0.8.b.d.0.1.0.0.2
663 6. There is a new ACL control called "debug", to enable debug logging.
664 This allows selective logging of certain incoming transactions within
665 production environments, with some care. It takes two options, "tag"
666 and "opts"; "tag" is included in the filename of the log and "opts"
667 is used as per the -d<options> command-line option. Examples, which
668 don't all make sense in all contexts:
671 control = debug/tag=.$sender_host_address
672 control = debug/opts=+expand+acl
673 control = debug/tag=.$message_exim_id/opts=+expand
675 7. It has always been implicit in the design and the documentation that
676 "the Exim user" is not root. src/EDITME said that using root was
677 "very strongly discouraged". This is not enough to keep people from
678 shooting themselves in the foot in days when many don't configure Exim
679 themselves but via package build managers. The security consequences of
680 running various bits of network code are severe if there should be bugs in
681 them. As such, the Exim user may no longer be root. If configured
682 statically, Exim will refuse to build. If configured as ref:user then Exim
683 will exit shortly after start-up. If you must shoot yourself in the foot,
684 then henceforth you will have to maintain your own local patches to strip
687 8. There is a new expansion condition, bool_lax{}. Where bool{} uses the ACL
688 condition logic to determine truth/failure and will fail to expand many
689 strings, bool_lax{} uses the router condition logic, where most strings
691 Note: bool{00} is false, bool_lax{00} is true.
693 9. Routers now support multiple "condition" tests.
695 10. There is now a runtime configuration option "tcp_wrappers_daemon_name".
696 Setting this allows an admin to define which entry in the tcpwrappers
697 config file will be used to control access to the daemon. This option
698 is only available when Exim is built with USE_TCP_WRAPPERS. The
699 default value is set at build time using the TCP_WRAPPERS_DAEMON_NAME
702 11. [POSSIBLE CONFIG BREAKAGE] The default value for system_filter_user is now
703 the Exim run-time user, instead of root.
705 12. [POSSIBLE CONFIG BREAKAGE] ALT_CONFIG_ROOT_ONLY is no longer optional and
706 is forced on. This is mitigated by the new build option
707 TRUSTED_CONFIG_LIST which defines a list of configuration files which
708 are trusted; one per line. If a config file is owned by root and matches
709 a pathname in the list, then it may be invoked by the Exim build-time
710 user without Exim relinquishing root privileges.
712 13. [POSSIBLE CONFIG BREAKAGE] The Exim user is no longer automatically
713 trusted to supply -D<Macro[=Value]> overrides on the command-line. Going
714 forward, we recommend using TRUSTED_CONFIG_LIST with shim configs that
715 include the main config. As a transition mechanism, we are temporarily
716 providing a work-around: the new build option WHITELIST_D_MACROS provides
717 a colon-separated list of macro names which may be overridden by the Exim
718 run-time user. The values of these macros are constrained to the regex
719 ^[A-Za-z0-9_/.-]*$ (which explicitly does allow for empty values).
725 1. TWO SECURITY FIXES: one relating to mail-spools which are globally
726 writable, the other to locking of MBX folders (not mbox).
728 2. MySQL stored procedures are now supported.
730 3. The dkim_domain transport option is now a list, not a single string, and
731 messages will be signed for each element in the list (discarding
734 4. The 4.70 release unexpectedly changed the behaviour of dnsdb TXT lookups
735 in the presence of multiple character strings within the RR. Prior to 4.70,
736 only the first string would be returned. The dnsdb lookup now, by default,
737 preserves the pre-4.70 semantics, but also now takes an extended output
738 separator specification. The separator can be followed by a semicolon, to
739 concatenate the individual text strings together with no join character,
740 or by a comma and a second separator character, in which case the text
741 strings within a TXT record are joined on that second character.
742 Administrators are reminded that DNS provides no ordering guarantees
743 between multiple records in an RRset. For example:
745 foo.example. IN TXT "a" "b" "c"
746 foo.example. IN TXT "d" "e" "f"
748 ${lookup dnsdb{>/ txt=foo.example}} -> "a/d"
749 ${lookup dnsdb{>/; txt=foo.example}} -> "def/abc"
750 ${lookup dnsdb{>/,+ txt=foo.example}} -> "a+b+c/d+e+f"
756 1. Native DKIM support without an external library.
757 (Note that if no action to prevent it is taken, a straight upgrade will
758 result in DKIM verification of all signed incoming emails. See spec
759 for details on conditionally disabling)
761 2. Experimental DCC support via dccifd (contributed by Wolfgang Breyha).
763 3. There is now a bool{} expansion condition which maps certain strings to
764 true/false condition values (most likely of use in conjunction with the
765 and{} expansion operator).
767 4. The $spam_score, $spam_bar and $spam_report variables are now available
770 5. exim -bP now supports "macros", "macro_list" or "macro MACRO_NAME" as
771 options, provided that Exim is invoked by an admin_user.
773 6. There is a new option gnutls_compat_mode, when linked against GnuTLS,
774 which increases compatibility with older clients at the cost of decreased
775 security. Don't set this unless you need to support such clients.
777 7. There is a new expansion operator, ${randint:...} which will produce a
778 "random" number less than the supplied integer. This randomness is
779 not guaranteed to be cryptographically strong, but depending upon how
780 Exim was built may be better than the most naive schemes.
782 8. Exim now explicitly ensures that SHA256 is available when linked against
785 9. The transport_filter_timeout option now applies to SMTP transports too.
791 1. Preliminary DKIM support in Experimental.
797 1. The body_linecount and body_zerocount C variables are now exported in the
800 2. When a dnslists lookup succeeds, the key that was looked up is now placed
801 in $dnslist_matched. When the key is an IP address, it is not reversed in
802 this variable (though it is, of course, in the actual lookup). In simple
805 deny dnslists = spamhaus.example
807 the key is also available in another variable (in this case,
808 $sender_host_address). In more complicated cases, however, this is not
809 true. For example, using a data lookup might generate a dnslists lookup
812 deny dnslists = spamhaus.example/<|192.168.1.2|192.168.6.7|...
814 If this condition succeeds, the value in $dnslist_matched might be
815 192.168.6.7 (for example).
817 3. Authenticators now have a client_condition option. When Exim is running as
818 a client, it skips an authenticator whose client_condition expansion yields
819 "0", "no", or "false". This can be used, for example, to skip plain text
820 authenticators when the connection is not encrypted by a setting such as:
822 client_condition = ${if !eq{$tls_cipher}{}}
824 Note that the 4.67 documentation states that $tls_cipher contains the
825 cipher used for incoming messages. In fact, during SMTP delivery, it
826 contains the cipher used for the delivery. The same is true for
829 4. There is now a -Mvc <message-id> option, which outputs a copy of the
830 message to the standard output, in RFC 2822 format. The option can be used
831 only by an admin user.
833 5. There is now a /noupdate option for the ratelimit ACL condition. It
834 computes the rate and checks the limit as normal, but it does not update
835 the saved data. This means that, in relevant ACLs, it is possible to lookup
836 the existence of a specified (or auto-generated) ratelimit key without
837 incrementing the ratelimit counter for that key.
839 In order for this to be useful, another ACL entry must set the rate
840 for the same key somewhere (otherwise it will always be zero).
845 # Read the rate; if it doesn't exist or is below the maximum
847 deny ratelimit = 100 / 5m / strict / noupdate
848 log_message = RATE: $sender_rate / $sender_rate_period \
849 (max $sender_rate_limit)
851 [... some other logic and tests...]
853 warn ratelimit = 100 / 5m / strict / per_cmd
854 log_message = RATE UPDATE: $sender_rate / $sender_rate_period \
855 (max $sender_rate_limit)
856 condition = ${if le{$sender_rate}{$sender_rate_limit}}
860 6. The variable $max_received_linelength contains the number of bytes in the
861 longest line that was received as part of the message, not counting the
862 line termination character(s).
864 7. Host lists can now include +ignore_defer and +include_defer, analagous to
865 +ignore_unknown and +include_unknown. These options should be used with
866 care, probably only in non-critical host lists such as whitelists.
868 8. There's a new option called queue_only_load_latch, which defaults true.
869 If set false when queue_only_load is greater than zero, Exim re-evaluates
870 the load for each incoming message in an SMTP session. Otherwise, once one
871 message is queued, the remainder are also.
873 9. There is a new ACL, specified by acl_smtp_notquit, which is run in most
874 cases when an SMTP session ends without sending QUIT. However, when Exim
875 itself is is bad trouble, such as being unable to write to its log files,
876 this ACL is not run, because it might try to do things (such as write to
877 log files) that make the situation even worse.
879 Like the QUIT ACL, this new ACL is provided to make it possible to gather
880 statistics. Whatever it returns (accept or deny) is immaterial. The "delay"
881 modifier is forbidden in this ACL.
883 When the NOTQUIT ACL is running, the variable $smtp_notquit_reason is set
884 to a string that indicates the reason for the termination of the SMTP
885 connection. The possible values are:
887 acl-drop Another ACL issued a "drop" command
888 bad-commands Too many unknown or non-mail commands
889 command-timeout Timeout while reading SMTP commands
890 connection-lost The SMTP connection has been lost
891 data-timeout Timeout while reading message data
892 local-scan-error The local_scan() function crashed
893 local-scan-timeout The local_scan() function timed out
894 signal-exit SIGTERM or SIGINT
895 synchronization-error SMTP synchronization error
896 tls-failed TLS failed to start
898 In most cases when an SMTP connection is closed without having received
899 QUIT, Exim sends an SMTP response message before actually closing the
900 connection. With the exception of acl-drop, the default message can be
901 overridden by the "message" modifier in the NOTQUIT ACL. In the case of a
902 "drop" verb in another ACL, it is the message from the other ACL that is
905 10. For MySQL and PostgreSQL lookups, it is now possible to specify a list of
906 servers with individual queries. This is done by starting the query with
907 "servers=x:y:z;", where each item in the list may take one of two forms:
909 (1) If it is just a host name, the appropriate global option (mysql_servers
910 or pgsql_servers) is searched for a host of the same name, and the
911 remaining parameters (database, user, password) are taken from there.
913 (2) If it contains any slashes, it is taken as a complete parameter set.
915 The list of servers is used in exactly the same was as the global list.
916 Once a connection to a server has happened and a query has been
917 successfully executed, processing of the lookup ceases.
919 This feature is intended for use in master/slave situations where updates
920 are occurring, and one wants to update a master rather than a slave. If the
921 masters are in the list for reading, you might have:
923 mysql_servers = slave1/db/name/pw:slave2/db/name/pw:master/db/name/pw
925 In an updating lookup, you could then write
927 ${lookup mysql{servers=master; UPDATE ...}
929 If, on the other hand, the master is not to be used for reading lookups:
931 pgsql_servers = slave1/db/name/pw:slave2/db/name/pw
933 you can still update the master by
935 ${lookup pgsql{servers=master/db/name/pw; UPDATE ...}
937 11. The message_body_newlines option (default FALSE, for backwards
938 compatibility) can be used to control whether newlines are present in
939 $message_body and $message_body_end. If it is FALSE, they are replaced by
946 1. There is a new log selector called smtp_no_mail, which is not included in
947 the default setting. When it is set, a line is written to the main log
948 whenever an accepted SMTP connection terminates without having issued a
951 2. When an item in a dnslists list is followed by = and & and a list of IP
952 addresses, the behaviour was not clear when the lookup returned more than
953 one IP address. This has been solved by the addition of == and =& for "all"
954 rather than the default "any" matching.
956 3. Up till now, the only control over which cipher suites GnuTLS uses has been
957 for the cipher algorithms. New options have been added to allow some of the
958 other parameters to be varied.
960 4. There is a new compile-time option called ENABLE_DISABLE_FSYNC. When it is
961 set, Exim compiles a runtime option called disable_fsync.
963 5. There is a new variable called $smtp_count_at_connection_start.
965 6. There's a new control called no_pipelining.
967 7. There are two new variables called $sending_ip_address and $sending_port.
968 These are set whenever an SMTP connection to another host has been set up.
970 8. The expansion of the helo_data option in the smtp transport now happens
971 after the connection to the server has been made.
973 9. There is a new expansion operator ${rfc2047d: that decodes strings that
974 are encoded as per RFC 2047.
976 10. There is a new log selector called "pid", which causes the current process
977 id to be added to every log line, in square brackets, immediately after the
980 11. Exim has been modified so that it flushes SMTP output before implementing
981 a delay in an ACL. It also flushes the output before performing a callout,
982 as this can take a substantial time. These behaviours can be disabled by
983 obeying control = no_delay_flush or control = no_callout_flush,
984 respectively, at some earlier stage of the connection.
986 12. There are two new expansion conditions that iterate over a list. They are
987 called forany and forall.
989 13. There's a new global option called dsn_from that can be used to vary the
990 contents of From: lines in bounces and other automatically generated
991 messages ("delivery status notifications" - hence the name of the option).
993 14. The smtp transport has a new option called hosts_avoid_pipelining.
995 15. By default, exigrep does case-insensitive matches. There is now a -I option
996 that makes it case-sensitive.
998 16. A number of new features ("addresses", "map", "filter", and "reduce") have
999 been added to string expansions to make it easier to process lists of
1000 items, typically addresses.
1002 17. There's a new ACL modifier called "continue". It does nothing of itself,
1003 and processing of the ACL always continues with the next condition or
1004 modifier. It is provided so that the side effects of expanding its argument
1007 18. It is now possible to use newline and other control characters (those with
1008 values less than 32, plus DEL) as separators in lists.
1010 19. The exigrep utility now has a -v option, which inverts the matching
1013 20. The host_find_failed option in the manualroute router can now be set to
1020 No new features were added to 4.66.
1026 No new features were added to 4.65.
1032 1. ACL variables can now be given arbitrary names, as long as they start with
1033 "acl_c" or "acl_m" (for connection variables and message variables), are at
1034 least six characters long, with the sixth character being either a digit or
1037 2. There is a new ACL modifier called log_reject_target. It makes it possible
1038 to specify which logs are used for messages about ACL rejections.
1040 3. There is a new authenticator called "dovecot". This is an interface to the
1041 authentication facility of the Dovecot POP/IMAP server, which can support a
1042 number of authentication methods.
1044 4. The variable $message_headers_raw provides a concatenation of all the
1045 messages's headers without any decoding. This is in contrast to
1046 $message_headers, which does RFC2047 decoding on the header contents.
1048 5. In a DNS black list, if two domain names, comma-separated, are given, the
1049 second is used first to do an initial check, making use of any IP value
1050 restrictions that are set. If there is a match, the first domain is used,
1051 without any IP value restrictions, to get the TXT record.
1053 6. All authenticators now have a server_condition option.
1055 7. There is a new command-line option called -Mset. It is useful only in
1056 conjunction with -be (that is, when testing string expansions). It must be
1057 followed by a message id; Exim loads the given message from its spool
1058 before doing the expansions.
1060 8. Another similar new command-line option is called -bem. It operates like
1061 -be except that it must be followed by the name of a file that contains a
1064 9. When an address is delayed because of a 4xx response to a RCPT command, it
1065 is now the combination of sender and recipient that is delayed in
1066 subsequent queue runs until its retry time is reached.
1068 10. Unary negation and the bitwise logical operators and, or, xor, not, and
1069 shift, have been added to the eval: and eval10: expansion items.
1071 11. The variables $interface_address and $interface_port have been renamed
1072 as $received_ip_address and $received_port, to make it clear that they
1073 relate to message reception rather than delivery. (The old names remain
1074 available for compatibility.)
1076 12. The "message" modifier can now be used on "accept" and "discard" acl verbs
1077 to vary the message that is sent when an SMTP command is accepted.
1083 1. There is a new Boolean option called filter_prepend_home for the redirect
1086 2. There is a new acl, set by acl_not_smtp_start, which is run right at the
1087 start of receiving a non-SMTP message, before any of the message has been
1090 3. When an SMTP error message is specified in a "message" modifier in an ACL,
1091 or in a :fail: or :defer: message in a redirect router, Exim now checks the
1092 start of the message for an SMTP error code.
1094 4. There is a new parameter for LDAP lookups called "referrals", which takes
1095 one of the settings "follow" (the default) or "nofollow".
1097 5. Version 20070721.2 of exipick now included, offering these new options:
1099 After all other sorting options have bee processed, reverse order
1100 before displaying messages (-R is synonym).
1102 Randomize order of matching messages before displaying.
1104 Instead of displaying the matching messages, display the sum
1106 --sort <variable>[,<variable>...]
1107 Before displaying matching messages, sort the messages according to
1108 each messages value for each variable.
1110 Negate the value for every test (returns inverse output from the
1111 same criteria without --not).
1117 1. The ${readsocket expansion item now supports Internet domain sockets as well
1118 as Unix domain sockets. If the first argument begins "inet:", it must be of
1119 the form "inet:host:port". The port is mandatory; it may be a number or the
1120 name of a TCP port in /etc/services. The host may be a name, or it may be an
1121 IP address. An ip address may optionally be enclosed in square brackets.
1122 This is best for IPv6 addresses. For example:
1124 ${readsocket{inet:[::1]:1234}{<request data>}...
1126 Only a single host name may be given, but if looking it up yield more than
1127 one IP address, they are each tried in turn until a connection is made. Once
1128 a connection has been made, the behaviour is as for ${readsocket with a Unix
1131 2. If a redirect router sets up file or pipe deliveries for more than one
1132 incoming address, and the relevant transport has batch_max set greater than
1133 one, a batch delivery now occurs.
1135 3. The appendfile transport has a new option called maildirfolder_create_regex.
1136 Its value is a regular expression. For a maildir delivery, this is matched
1137 against the maildir directory; if it matches, Exim ensures that a
1138 maildirfolder file is created alongside the new, cur, and tmp directories.
1144 The documentation is up-to-date for the 4.61 release. Major new features since
1145 the 4.60 release are:
1147 . An option called disable_ipv6, to disable the use of IPv6 completely.
1149 . An increase in the number of ACL variables to 20 of each type.
1151 . A change to use $auth1, $auth2, and $auth3 in authenticators instead of $1,
1152 $2, $3, (though those are still set) because the numeric variables get used
1153 for other things in complicated expansions.
1155 . The default for rfc1413_query_timeout has been changed from 30s to 5s.
1157 . It is possible to use setclassresources() on some BSD OS to control the
1158 resources used in pipe deliveries.
1160 . A new ACL modifier called add_header, which can be used with any verb.
1162 . More errors are detectable in retry rules.
1164 There are a number of other additions too.
1170 The documentation is up-to-date for the 4.60 release. Major new features since
1171 the 4.50 release are:
1173 . Support for SQLite.
1175 . Support for IGNOREQUOTA in LMTP.
1177 . Extensions to the "submission mode" features.
1179 . Support for Client SMTP Authorization (CSA).
1181 . Support for ratelimiting hosts and users.
1183 . New expansion items to help with the BATV "prvs" scheme.
1185 . A "match_ip" condition, that matches an IP address against a list.
1187 There are many more minor changes.
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